Grinding machine



Aug- 4, 1953 H. A. slLvEN 2,647,349

GRINDING MACHINE Original Filed Aug. 4, 1951 15 Sheets-Sheetl w o www um Em v 1 or MN n m\\o\\nm ou? Hm mam w Mmwmwwywwwm ull-illjrfyemor HERBERT ALS/I vE/v 5 y fowy Aug. 4, 1953 Original Filed Aug. 4, 1951 l5 Sheets-Sheet.. 2

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Iweytor HEEBERTA .5/1. VEN

Allg' 4, 1953 H. A. slLvEN 2,647,349

GRINDING MACHINE original med Aug. 4. 1951 15 Sheets-Sheet 3 numnnuunnm IWI/616m ya W HERBERT A51/ VEN- 3 7 57M LO fcowfey Aug. 4, 1953 H. A. slLvEN 2,647,349

GRINDING MACHINE original Filed Aug. 4, 1951 1S sheets-sheet 4 Z'kI/eltd Y HERBERT A. 51m/EN ccor'ney Aug. 4, 1953 H. A. slLvEN l .256475349 GRINDING MACHINE Original Filed Aug. 4, 1951 15`Sheets-Sheet 5 Im/elztor HERBERT A. S/L VEN Hfe rwey Aug. 4, 1953 H. A. slLvEN 2,647,349

GRINDING MACHINE Original Filed Aug. 4, 1951 15 Sheets-Sheet 6 fig-6 Iza/cator- HERBERT A. S/LVEN @www Aug. 4, 1953 H. A. slLvEN 2,647,349

GRINDING MACHINE Original Filed Aug. 4, 1951 15 Shee'c's--S'hel 8 Aug. 4, 1953 H. A. slLvEN 2,647,349

GRINDING MACHINE Original Filed Aug. 4, 1951 15 SheetsSheet 9 Inventar HERBERT A. 5u. VEN

mfowfey Aug. 4, 1953 H. A. slLvEN GRINDING MACHINE 15 Sheets-Sheet 10 Original Filed Aug. 4, 1951 aan Myer/tor HERBERT A. S/L VEN *E A. z

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Aug. 4, 1953 H. A. slLvEN 2,647,349

GRINDING MACHINE Original Filed Aug. 4, 1951 15 ShBetS-Sheet 12 /12 Pam P523@ P57 277 30o 5f@ Z961 5'? i HERBERT A. .5l/ VEN Aug. 4, 1953 H. A. SILVEN 2,647,349

GRINDING MACHINE Original Filed Aug. 4, 1951 15 Sheets-Sheet 15 HERBERT A. SILVEN A Aug. 4,l 1953 H.`A. slLvEN 2,647,349

- GRINDING MACHINE Original Filed Aug. 4, 1951 15 Sheets-Sheet 14 .Pm/cnt o r HERBERT A. S/L VEN @ym L tcorney Aug. 4, 1953 Y H. A. slLvEN 2,647,349

GRINDING MACHINE Original Filed Aug. 4, 1951 15 Sheets-Sheet 15 ql 77\CK/NG FEED mi ng. 25 i FEED oF UPPER .5L/DE F550 oF m UPPER sL/os /7 4-5/4 :t L u l WiL- 454-? SSSSS 45? 486 TACK/N6 FEED TACK/'N6 F550 Inventar HERBERT A. S/LVEN rfforle/V Patented Aug. 4, 1953 GRINDING MACHINE Herbert A. Silven, Worcester, Mass., assignor to.r Norton Company, Worcester, Mass., a corporation of Massachusetts Original application August 4, 1951, Serial No.

240,378. Divided and this applicationrJune 19,' 1952, Serial N0. 294,311 v A The invention relates to grinding machines, and more particularly to a universal-type grinding machine. This application is a division of my co-pending application, Serial No. 240,378 filed August 4, 1951.

One object of the invention is to provide a simple and thoroughly practical grinding machine for grinding or regrinding a wide variety of workpieces. Another object is to provide a grinding machine whereby workpieces may be ground either on centers or may be ground while mounted on a face plat-e. Another object is to provide a double swivel wheel head whereby a wide variety of 'angular surfaces on a workpiece may be ground.

A further object of the invention is to provide hydraulically actuated grinding wheel carriage and grinding wheel slides with hydraulically actuated nut and screw mechanism for traversing the carriage to position the grinding wheel relative to the work to be ground, and also to feed the grinding wheel transversely' to grind the workpiece to the desired and predetermined extent. Another object is to provide a hydraulically actuated electrically controlled mechanism for remotely controlling the positioning movement of the grinding wheel carriage. Another object is to provide a hydraulically actuated electrically controlled mechanism independently to feed both of the cross slides by a remote control thereof. Another object is to provide independent manually operable remote control mechanisms for the grinding wheel carriage traversing mechanism and for both an upper and lower cross slide feeding mechanisms in which there is no mechanical connection. between the control mechanism and the actuating mechanism therefor whereby the carriage and slides may be precisely adjusted during a grinding operation. A further object is to provide a tacking-type feed mechanism whereby an angularly arranged wheel spindle may be manually adjusted axially to impart a precise transverse feeding movement of the grinding wheel. Other objects will be in part obvious ory in part pointed out hereinafter.

The invention accordingly consists in the fea-` tures of construction, arrangements 0i parts, as will be exemplified in the structure to be hereinafter described, and the scope 'of the application of which will be indicated in the following claims.

One embodiment of the invention has been illustrated in the drawings, in which:

v-Fig. 1 is a front elevation of the improved grinding.' machine; f

' Fig. 2 is afragmentary plan View of the grind-l 4 Claims. (Cl. 51--166) ing machine with Ithe'upper `control panels and mounting therefor removed;

Fig. 3 is a combined electric and hydraulic. diagram of the actuatingmechanism of the machine and the controls therefor;

Fig. 4 is an hydraulic diagram, on an enlarged scale, of the` controls and actuating vmechanism for the longitudinally movable carriage;

Fig. 5 is a combined electrical and hydraulic diagram, on an enlarged scale, of the controls and actuating mechanism for' the upper slide;

Fig. 6 is a combined electrical and hydraulic diagram on an enlarged scale, of the controls and actuating mechanism for the lower slide;

Fig. '7 is a verticalv sectional view, on an enlarged scale, through the headstock;

Fig. 8 is a vertical cross-sectional view, yon an enlarged scale, taken approximately on the line 8-8 of Fig. 1, through `Ythe grinding machine;

Fig. 9 is a fragmentary detail View, on an enlarged scale, ofA the grinding wheel carriage traversing and positioning mechanism;

Fig. ll0 is a fragmentary front elevation, partly in section on an enlarged scale, of the reversing control mechanism for the longitudinally movable carriage; f

Fig. 11 is a plan View of the mechanism shown in Fig. 10;

Fig. 12 is a fragmentary cross-sectional view,

taken approximately on the line |2-.-l2 of Fig. 11;

- larged scale, of the fine adjusting mechanism for controlling the swivelling movement of the upper slide and its supporting slide;

Fig. 15is a vertical sectional View, taken approximately on the line I5-I 5 of Fig. 14;

Fig. 16 is a fragmentary front elevation, on an enlarged scale, of the lower control station on the front ofthe machine, having the cover removed so asl to show the control valves;

Fig. 17 is a fragmentary vertical sectional view,

taken approximately on the line l'I-l 1 of Fig. 16,4

through the manual control for the upper Slide; Fig. 18 is a fragmentary sectional view, taken approximately on the line IS--IB of Fig. 17;

Fig. 19 is a fragmentary front elevation, on an enlarged'scale, of the upper-control station larged scale, through the grinding wheel head,y

'i (i. showing the wheel spindle positioning mechanism;

22 is a vertical sectional view, taken approximately on the line Z2-22 of Fig. 21, through the wheel spindle actuating mechanism;

Fig. 23 is a front elevation o an internal grinding attachment removably mounted on the front of the Wheel head;

Fig. 24 is a left-hand end elevation of the internal grinding attachment as shown in Fig. 23;

Fig. 25 is a diagrammatic view showing the grinding machine set-up to employ a taclcins' feed;

Fig. 26 is a diagrammatic view showing the grinding machine set-up for a shoulder upside face grinding operation;

Fig. 27 is a diagrammatic view showing the grinding machine set-up for a surface grinding operation; and

Fig. 28 is a diagrammatic view showing the grinding machine set-up for an internal grindingoperation.

The improved grinding machine has been iilustrated in the drawings comprising a base lo which supports a swivel table il. rEhe swivel table H is arranged to pivot on a stud I2 which is xedly supported on the base l0. A pair of guides land clamping blocks I3 and i4 are' provided on the base It for engaging and clamping opposite ends of the swivel table H in adjusted position to the base I0.

The swivel table H serves as a support for a headstock l and a ootstock l for rotatably supporting a workpiece during a grinding operation.

The headstock l5 is provided with arotatable headstock spindle I7 which is journalled in antifriction bearings I8 and t9 Within the headstcck l5. The headstock spindle H is provided wit-ha headstock center 2t for rotatably supporting the left-hand end of a workpiece. The footstock I6 is similarly provided with a footstock center 2l for rotatably supporting the right-hand end of a workpiece during a grinding operation.

A suitable driving mechanism is provided for the headstock spindle comprising an electric motor 25 mounted on top of the headstock i5. The motor 25 is provided with an armature shaft 26 having a multiple V-groove pulley'21 which is connected by multiple V-belts 2S with a pulley 2E mounted on a shaft 30.. The shaft Bil also supports a multiple v-groove pulley 3i which is connected by multiple V-belts 32 with a multiple V-groove pulley 33 mounted on a rotatable shaft 313. The shaft 34 is connected by means of a sprocket and link chain (not sho-Wn) with a sprocket 3l which is journalled on anti-friction bearings 38 on the w-heel spindle il. The Spindle is arranged so that it may he. operated as a live spindle headstock or a dead center. headstock. rIhe sprocket 31 is connected by a stud 35 with a face plate or driving plate 3,9. In the position as illustrated rotary motion transmitted t0 the sprocket 31 will be imparted to rotate the Work driving plate 39 while the Work center remains stationary. The driving plate 39 is provided with a driving pin 40 which is arranged to engage either a portion of the workpiece to be ground or a Work driving dog mounted thereon.

A suitable mechanism is provided for holding the headstock spindle H stationary when it is desired to operate the headstock for dead center grinding.- This, meohanismmay comprise agear 4l which is keyed on the spindle ll (Fia-'7).'

A slidably mounted locking pin is arranged to be moved into engagement with the teeth oi the gear li to look the spindle il or may be withdrawn from engagement therewith if a live spindie grinding operation is to be performed. The locking pin` l2 is slidably mounted within an aperture 43 formed Within the headstook i5. The locking pin 42 is connected by a screw ed with a block d having a cylindrical aperture 36 therein Which engages an eccentric portion 1li of a rotatable shaft 518. The shaft it is journalled in bearings 49 and 56 which are mounted in the headstock l5. An actuating knob 5l mounted on the right-hand end of the shaft to facilitate actuation of the locking pin d2.

If it is desired to operate the headstock l5 as a live spindle headstoclr, the stud 35 may be moved toward the left (Fig. 7) into engagement with a hole in a plate to which is keyed to the headstock spindle il'. The actuating knob 5i is then rotated to Withdraw the locking pin d?. thereby unlocking the spindle il, In this position `oi the parte, it will be readily apparent that rotary motion transmitted to the sprocket 3l Will be imparted through the stud 35 to rotate the Work driving plate 3d and also to rotate the plate 3S and the headstock spindle l?.

The heads-took 5 is also provided with a relatively large iace plate 55 which is mounted on the left-hand end of the headstock spindle il (Fig. 7). It is desirable to provide a suitable swivel adjustment for the headstock le so that the parts may be shifted to facilitate either a center type grinding operation or a face plate type grinding operation. The headstock i is pivotally supported by a vertically arranged stud 56 carried by a base plate 5l which is clamped onto the upper surface of the swivel table Il. A pair of clamping bolts 58 and 5i! are mounted on diametrically opposite sides of the pivot stud 5G. The clamping bolts Eil and 53 pass through clearance holes in the heads'tock i5 and. their heads are slidably supported in a circular T-slot to formed in the base plate It will oe readily apparent from the foregoing disclosure that by loosening the clamping bolts 53 and 5d, the headstock i5 may be swivelled through 360 so as to present either the driving plate 39 and the Work center 20 into an operative position, or to po` on the headstock i5 so that the face plate is in the desired position for a grinding operation.

'The grinding machine as illustrated, is a travelling Wheel type machine in which the grinding Wheel to be hereinafter described is supported by a longitudinally traversable grinding Wheel carriage which is arranged to slide longitudinally on a V-Way 66 and a flatway B'i (Figli) formed on the upper surface of the base Eil. The grinding Wheel carriage 65 is provided with a suitable traversing mechanism comprising a nut S8 depending from the underside of the carriage S5. The nut 68 meshes with a rotatable screw The screw 59 is journalled in spaced bearings le and 1I supported by the base IG. The rotatable screw 69 is provided with a gear 'i2 which meshes with a gear 'I3 mounted on a rotor shaft 'it of a fluid motor 15. Fluid under pressure is admitted to and exhausted from the i'luid motor 'ld through a pair of pipes 301 and Sli? in a manner to be hereinafter described.

The grinding wheel carriage 55 is provided with a transversely arranged V-way St and a flat-- Way Si which serve as supports for a cross-slide 82, The upper portion of the cross Aslide 82is circular in` shape and supports a s vvivel 4plate 83.

The swivel plate 83 is arranged to swivel about a vertically arranged pivot stud 84. The swivel plate 83 is provided with a transversely arranged V-way 85 and a flatway 86 which are arranged to support a transversely movable wheel slide 81. The upper portion of the wheel slide 81 is circular in shape and is arranged to support a wheel head 88. The wheel head 88 is arranged to swivel about a vertically arranged pivot stud 89 carried by the Wheel slide 81. The wheel head 88 serves as a support for a rotatable wheel sp-indle 88 which is journalled in suitable bearings 428 and 42| mounted within the wheel head 88. The wheel spindle 98 supports a pair of grinding wheels 8| and 82 at opposite ends thereof. The spindle 98 portion of the wheel head 88. 'I'he motor 93 is y provided with a motor shaft 94 carrying a multiple v-groove pulley 95. The pulley 95 is connected by multiple V-belts 86 with a multiple V- groove pulley 81 mounted on the wheel spindle 88. It will be readily apparent that actuation of the motor 83 Will be imparted to transmit a rotary motion to the grinding wheels 9| and 82.

A nut and screw feeding mechanism is provided between the carriage 65 and the lower cross slide 82 whereby a transverse movement of the wheel head together with the intermediate parts may be obtained. This mechanism comprises a rotatable screw (Fig. 13) which is supported by a pair of spaced anti-friction bearings I0| and |82 mounted in the base I0. The screw |80 meshes with a nut |03 which is flxedly mounted on the underside of the cross slide 82. The feed screw |08 carries a gear |04 which meshes with a gear |05. The gear |05 is mounted on a rotor shaft |86 of a fluid motor |01. Fluid under pressure is conveyed to and from the fluid motor |81 through a pair of pipes 282 and 283 in a manner to be hereinafter described.

A nut and screw feeding mechanism is provided between the swivel plate 83 and the upper slide 81. A rotatable feed screw I I8 is supported at one end in anti-friction bearings III and ||2 which is keyed within a cylindrical aperture I I3. The other end of the feed screw ||0 is slidably keyed within a rotatable sleeve II4. The sleeve I4 is journalled in anti-friction bearings I5 and ||6 which are supported by the swivel plate 83. A reduced cylindrical portion I I1 of the feed screw I I8 is slidably keyed within an aperture I8 in the sleeve I4 to facilitate an axial movement of the feed screw I |8 for rapidly moving the wheel slide 81 and the wheel head 88 intoan operative or inoperative position. v

In order to impart a feeding movement to the upper slide 81, a bevel gear |24 is keyed on the right-hand end of the sleeve I I4 (Figs. 3 and 13). The bevel gear |24 meshes with a bevel gear |25 carried by a shaft |28. The shaft |26 is connected by a pair of bevel gears |21 and |28 with a rotor shaft |28 of a fluid motor |30. Fluid under pressure is admitted to and exhausted from the motor |30 through a pair of pipes |3| and |32 in a manner to be hereinafter described. It will be readily apparent from the foregoing disclosure that a double swivel adjustment is provided, namely, the wheel head 88 may be swivelled relative to the upper slide 81 and the swivel plate 83 mayVV be swivelled relative to the lower slide 82 to facilitate grinding angular and shouldered or side faces on a workpiece being ground. In any position of the swivel plate 83, the wheel head 88, the lowerslide 82 may be fed trellSversely relative tothe base and the upper slide 81 may be fed transversely relative to the swivel plate 83. By a combination of feeding movements, any angular surface may be ground on a workpiece either mounted on the work centers 20 and 2| or on the face plate 55.

A fluid pressure system is provided for supplying fluid under pressure to the various operating mechanisms of the machine. This system may comprise a motor driven fluid pump |35 (Fig. 3)

which draws fluid through a lpipe I 36 from a fluid reservoir I 31. The pump |36 forces iiuid under pressure through-a pipe |38 to the various operating mechanisms'of the machine. A pressure relief valve |38 is connected with the pipe line |38 so that excess fluid under pressure may be bypassed through a pipe |48 into the reservoir |31.

It is desirable to provide a rapid approaching movement for the upper slide 81 to facilitate rapidly moving the grinding wheels to and from an operative position before and after a grinding operation. A hydraulically operated mechanism is provided comprising a cylinder |45 which is arranged in axial alignment with the feed screw I|0. The cylinder |45 contains a slidably I mounted piston |46 which is connected to one end of a piston rod |41. The other end of the piston rod' |41 is xedly connected to the slidably mounted sleeve I I2 (Fig. 13) so that movement of the piston |46 will be imparted to cause an axial movement of the feed screw |I0 rapidly to move the upper slide 81 tovand from an operative position. A suitable control mechanism is provided for controlling the admission to and exhaust of fluid from the cylinder |45. This control mechanism may comprise a control valve |48 having a slidably mounted valve member |48 which is arranged to be shifted by means of fluid under pressure admitted to and exhausted from chambers formed in the opposite ends of the valve |48. A pilot valve |50 is provided for controlling the shifting movement of the valve member |48. rlhe pilot valve |50 is normally held in a right-hand end position by means of a compression spring I 5|. A solenoid S8 is provided for shifting the pilot valve into a left-hand end position so as to admit fluid under pressure into the left-hand end chamber to shift the valve member |48 toward the right so as to change the direction of fluid under pressure passing through a pair of pipes I 52 and |53 which connect the valve |88 with the cylinder |45. A switch PBH or a switch PBI 8 may beactuated to energize a relay switch CRI to energize the solenoid S8 to initiate a rapid forward movement of the upper slide 81. A switch PBI or a switch PB|2 may be actuated to break the circuit thereby deenergizing the solenoid S8 to return the upper slide 81 to a rearward position.

It is desirable to provide suitable means for slowing down the rapid approaching movement before the piston |46 reaches the end of its stroke in either direction. This is preferably accomplished by providing a pair of throttle valves |54 and |55 which are arranged to control the admission ofiiuid into the cylinder |45 after the main port has been closed. A pair of ball check valves I54a yand |55a are provided to allow fluid under pressure to pass in one direction unrestricted by bypassingaround the throttle valves |54 and |55 respectively.

In a large universal type machine, such as disclosed, it is desirable to prov-ide adequate controls for the various mechanisms of the machine so that the operation thereof may be readily controlled from the front of the machine b-ase or from' an operatorscontrol station |68 or I6| A0,11

autres@ the longitudinally recieroable carriage t (Fia 2). A control unit |52 is mounted on the front of the maohne base. (Fejll all@ cons trol unit is provided with a. plurality or hand wheels consisting or a hand wheel |63 for controlling the movement of; the upperslide 8l, a hand wheel |64 for controlling the lower slide 82 and a hand wheel |525 for controlling the car.- riage te. An electrical control panel |56 iS mount-,ed above the control unit |52* (Fiss. 1 and 16) whereby the various units may be, controlled from the iront or the machine base.

A similar control unit 1:61a is mounted on a bridge-type frame it; Wigs. l and 19) which is. Supported on the longitudinally movable carriage The cont-rel unit: leila is provided with a plurali-tv of nano wheels, a hand Wheelk 5.3 lor controlling the upper slide Sli., a hand wheel iddo, for centrelling the lower slide E2 and a hand wheel llic; for controlling the movement of the carriage 65. An electrical control panel Illo is mounted on the uuner De." la to facilitate controlling the electrical or the machine. Au electric light bull; |56 on the. upper control unita |62@ is. connected .etlie between the solenoid Sii and one side or the power lines which is illuminated when the sole noid SS: is energized visibly to indicate that the upper slide is in a.` forward position.

In order that the upper control unit |536; may be readily accessible and within easy rea-ch of either the control station itil or lili, the control unit is preferably pivotilly mounted on a pivot .f1-tud l (Fig. :lill sup-ported on the brifigwtyl' frame les. The bridgeftyneframe |58 is provided with an arcuate. shaped plate |89 which serves as a slideway for the control unit |5211. A clamping screw il@ (Figs. l and 19) passes through an elongated arcuate slot Vil (Fig. 2Q) formed in the plate |59 and is screw threaded into a nut i12 carried by the unit lZa. Et will he readily apparent from the foregoing disclosure that hy loosening the clamping screw |153, the control unit |52@ together with the electrical control panel i556 may be readily swivelled on the pivot stud ll so as to bring the hand wheels |6305, la and la together with the Vpus-h buttons on the electrical control panel la within easy reach of the control station itil and 18|.

The hand wheels |83, Ita, Hit, iSAa, iBS and |55a are each operatively connected to actuate. independent control valves in a manner to he hereinafter described. The. mechanical donnee: tions between these hand wheels and the respec: tive control valves are identical in construction, consequently only one of these mechanisms has been illustrated in detail. As shown in Figs. 16, 17 and 1S, the hand Wheel |63 is keyed on a sleeve I'lil which is in turn rotatably supported on a fixed shaft H. A gear l'iB is-keyed on the sleeve |14 and meshes with a rack bar The rack har is connected by means of a rod |18 with a valve stem |79 of a control valve |30. A cornpression spring |8| is provided normally to hold the valve stem |19 and the associated parts in a central position. A cam |82 is keyed on the sleeve Vit and is arranged to xactuate either an actuating arm |83 or an actuating arm |84 of a limit switch LSI or a limit switch L52 respite.- tively, depending upon the direction of rotation of the hand wheel |63 and the sleeve |14.

In order to provide precise and positive control of the duid motors lill and |30 for controlling transverse movements of the lower slide 8,2 and the upper slide 31, respectively. uid Bilder pres ci the. control unit.

Ft e sure isnormally supplied toboth pipes leading te each of the fluid motors. When it is desired,-

to impart a. feeding motion either to the lower slide 32 or the upper slide Si', the fluid pressure to one side or the other of the motor is opened to theexhaust thereby allowing,f the motor to transmit the desired feeding movement to either the feed screw |011 or the feed screw H0. AS illustrated in. the drawings, an inching feed may he obtained. by a slight rotation of the hand Wheel |53 in a countercloclcwise direction which serves toshiit the valve stem H9 so as to open an exe haust port |85 in the valve i so that fluid may exhaust through a pipe |86, through a throttle.

valve |8 and through an exhaust pipe |88 into the reservoir- 3,|. vBy controlling the throttle valve lill,l the rate of rotation of the feed screw` HB may be readily varied as desired. A similar port 89 is provided so that when the hand Wheel lgl rotated in .a clockwise direction, the valve stem |19 will be shifted so as to open the port e9 `which allows fluid to exhaust from the other4 side el the motor through the same throttle valve il into the exhaust pipe |l8 to control the rota.. 'tion of the feed screw lie the opposite direcE tion.

A. suitable mechanism is provided normally to limit the rotation of the hand wheel |63 in either direction so that only -suflicient movement is irnparted to the valve stem |79 to open either the port |85 or the portV IEE) depending upon the direction of rotation of the hand wheel E63. This mechanism may comprise a slidahly mounted stop pin lill. (Fig. 17) which is supported by the hand .wheel H63. The rightfhand end of the pill lS-ll rides with an elongated arcuate slot I9! hav-.- ing a pair of stop surfaces |93 and |94 formed in a plate le?! which nxedly mounted relative to the valve |65.

For a rapid transverse movement of the upper slide lil, it is desired to bypass fluid around the throttle valve 3 so that a rapid movement of theunper slide lll may he detained when desired. A roch arm |65 is pivotally supported on the hand wheel N63. When it is dslred to obtain a (Fig. 1'?) to withdraw the pin |S|l from the slotl lill so that an increased rotary motion of the hand wheel |63 is permitted. The increased rotary motion of the hand Wheel |63 serves to cause an increased motion of the valve stem il@ in either direction depending upon the direction or rotation of the hand wheel |63 so as to open either an exhaust port or an exhaust port |91 which exhaust fluid from the motor |38 directly through the pipe |88 into .the reservoir |61.

The hand wheel |530. is supported cn a shaft Illia carried by the upper control unit |620.. A cam i820, is keyed to rotate with the hand wheel |630, and is arranged to aotuate the actuating arios |3354 and |8441 of a pair of limit switches LSE) and LSG respectively when the hand wheel is rotated in either direction. A gear lll/5o is keyed te rotate with the hand wheel Iota and meshes with a raclf: har ll'l'a. The rack. har Illa is connected hy a rod Ila with a valve stem Hilo of a control valve illa. A compression spring isla serves normally to hold the valve stem Illia in a central position. The valve Illa is identical in, attenuation with the valve Hit and is provided with ports ll, |8311, Hita and lilla which are connected with the pipes la and 88 respectively. .In the normal. entretien of the hand Wheel It@ that for inet.' ,e ieee, the hand, wheel |6341 is rotated either in a clockwise direction or counter-clockwise direction to vopeneither the port |89a or the port |85a so that fluid may exhaust through the pipe |8611, through the common throttle valve |81 and out through the exhaust pipe |88. If it is desired to cause a rapid movement of the upper wheel slide, the rock arm |95a is rocked to withdraw the slide pin (not shown) to allow a further rotaryfmotion of the hand wheel |'63a so as to open either the ports |96a or |8'la so that fluid exhausting from the system may bypass the throttle valve |81 and pass directly into the exhaust pipe |88. The hand wheels |63 and |63a as above described are connected in parallel so that actuation of either hand vwheel operates to control the stopping and starting of the upper slide motor |30. The mechanisms above described controlled by the hand direction.

It is desirable to provide a pick feed mechanism whereby the upper slide may be advanced in a forward or rearward direction by a predetermined increment each time the mechanism is actuated. This mechanism is preferably arranged so that a pick or incremental feed may be obtained either in a forward direction for an external grinding operation or in a rearward direction for an internal grinding operation as desired. This mechanism may consist of a fluid actuated control valve 200 having a slidably mounted valve member 20| which is normally held in a central position by a pair of compression springs 202 and 203 located in the opposite end chambers of the valve 200. A pilot valve 204 is provided for controlling the shifting movement of the valve 200. The pilot valve 204 is normally held in a central position as illustrated in Fig. by opposed compression springs. A solenoid SI and a solenoid S2 are provided to shift the pilot valve 204 in 0pposite directions to control the direction-of flow of fluid to the fluid motor |30. When the solenoid SI is energized, the valve 204 is shifted toward the right to pass uid into the right-hand end chamber of the valve 200 to shift the valve member 20| toward the left so that fluid under pressure from the pressure pipe |38 may pass through a valve chamber 205 and out through the pipe |3| so that when fluid is exhausted from the other side of the motor a transverse feeding movement may be obtained in a forward direction. Similarly when the solenoid S2 is energized the valve member 20| is shifted toward the right so that fluid under pressure in the pressure line |38 may pass through the valve chamber 205 and through the pipe |32 to the motor |30.

A suitable electric control is provided for actuating the pilot valve 204. 'I'his mechanism may comprise a pair of pushbutton switches PBT on the upper control unit |62a and PB8 on the lower control unit |62. The pushbutton switches PB'I and PBS are connected in parallel to start an electric timer 22| to close a circuit. Aselector switch SL2 is provided so that either a magnetic switch CRS or a magnetic switch CRIU may be actuated to energize the solenoids SI and S2 respectively so as to cause either a feeding movement in a forward or rearward direction depending uponv the set-up of the machine. If the selector switch is rotated in a clockwise direction, the magnetic switch CRB is connected so that when either the pushbutton switch PBT or PBS are actuated the timer 22| will be started to energize the switch CRB thereby energizing the solenoid Sl to shift the valve member 20| to io' cause a forward feeding increment of theup'er slide motor |30.

Similarly if the selector switch is rotated in a. counter-clockwise direction the magnetic'switch CR|0 is connected so that when the timer 22| is set in motion the magnetic switch CR|0 is closed to energize the solenoid S2 so as to shift the valve member 20| ina direction toward the right to pass fluid under pressure so as to cause a rearward feeding increment of the motor |30. The electric timer 22| is adjustable so that the duration of the pick or increment may be adjusted as desired. After the timer has run for the set period, magnetic switch CRB or the magnetic switch CR|0 is deenergized thereby deenergizing either the solenoid SI or the solenoid S2 to allow.l the valve member 20| to return to a central or neutral position.

In order to give a precise control of the pick or incremental feed, a suitablemechanism is provided for controlling the exhaust of fluid from the motor |30. This mechanism preferably comprises a solenoid valve 209 having a slidably mounted valve member 2|0 which is lnormally held in a right-hand end position by means of a compression spring 2| A solenoid S5 is provided which when energized serves to shift the valve member 2|0 toward the left. vA pipe 2|2 connects the control valve 200 with a metering valve 2 3. The metering valve 2 3 is a fluid actuated valve. AIn the position of the valves 209 and 2|3 (Fig. 5) fluid under pressure from the pipe |38 passes through a valve chamber inthe valve 209, through a pipe 220 into a left-hand end chamber of the valve 2|3 to maintain the valve 2 I3 in its extreme right-hand end position. When either the magnetic switch CRB or CR|0 is energized, contactors therein serve to close a circuit to energize the solenoid S5 so that fluid from the pressure pipe |38 may pass through the valve 200, through a pipe 2|4, through a throttle valve 2|5 into the right-hand end chamber of the valve 2|3 to move the valve 2|3 toward the left. During this longitudinal shifting movement of the valve 2|3, fluid may exhaust from the motor |30 through the valve 200, through the pipe 2|2, through a valve chamber 2| 6 in the valve 2|3 through a pipe 2|'|, a ball check valve 2|8 and a throttle valve 2|9 and pass through the pipe 2'20, through the valve 209 into the common exhaust line |88. The speed of movement of the valve 2 |3 is regulated by the setting of the throttle valve 2|5 so that a predetermined amount of fluid may be metered therethrough. The rate of exhaust of fluid fromthe motor |30 is controlled by the setting of the throttle valve 2 I9. A signal light 222 is provided so that the operator may know when the pick or incremental feed is in operation. A second pick feed cannotl be obtained until the rst pick feed has been completedand the timer reset to` its initial position. An electric light bulb 222 on the upper control unit |620, is connected in series between themagnetic switches CRB- CRIB and the solenoid S5 and also connected in series between switches CRS-CRT and the solenoid S6 visibly to indicate that the pick feed ofthe upper slide 81 or the lower slide 82 is operative under control of the timer 22| or the timer 28| respectively. 

